1. Field of the Invention
The subject invention pertains to the hazards of hydrogen sulfide and more specifically to a personal system for responding to an excessive amount of hydrogen sulfide.
2. Description of Related Art
Hydrogen sulfide, H2S, is a toxic gas that often accompanies the production of gas, oil and water. H2S can usually be contained, but if it escapes, an H2S monitor can be used for alerting personnel in the area. In response to sensing about 10 to 20 ppm of H25, typical H2S monitors will sound an alarm that warns of the danger. Once the alarm sounds, personnel often have sufficient time to vacate the area. In some cases, however, someone or everyone in the area may be overcome by the gas and fall to the ground. Since H2S is heavier than air, an unconscious person lying on the ground may continue breathing the toxic gas. If outside help is not quickly summoned to the area, eventually those continuing to breath the gas may die.
U.S. Pat. No. 6,252,510 discloses an H2S system that calls for outside help upon sensing an excessive amount of H2S at a distant location. The system appears to be designed for an established chemical plant where the H2S monitor is at a fixed, known location. Such a system may be fine for monitoring hydrogen sulfide gas at a particular location, but it may be inadequate for protecting an individual moving from one location to another.
In the case of an outdoor well site that includes a stationary H2S monitor, an undetected problem may occur if a hydrogen sulfide leak is downwind of the H2S monitor, and an oilfield worker is downwind of the leak. The worker may be exposed to the hydrogen sulfide gas, but the monitor may fail to detect the leak.
Today, H2S monitors, various fault monitoring systems, and wireless communications are used for monitoring conditions at a well site. SCADA (Supervisory Control And Data Acquisition) is perhaps the most common system for monitoring the pumping conditions at a well site and for communicating pumping-related faults to another location. Various transducers that sense a pumping condition (e.g., fluid pressure, fluid level, power failure, etc.) are hardwired to the hardware portion of the SCADA system. Hardwiring a person-carried H2S monitor to a SCADA system, unfortunately, would drastically limit the portability of the H25 monitor. Thus, person-carried H2S monitors are generally stand-alone devices that simply sound an alarm upon sensing a certain concentration of hydrogen sulfide gas. Such an alarm, however, may not necessarily alert outside help.
Consequently, a need exists for a completely portable, person-carried H2S monitor that can summon help from a remote location. It may be beneficial to have such a system where an existing conventional H2S monitor can be incorporated into a conventional SCADA system, thereby avoiding the cost of an entirely new monitor and communication system.